King County will close both directions of NE Woodinville Duvall Road near the intersection of NE 172nd Street from Monday, July 17 to Tuesday, Aug. 15. This closure is necessary for the removal and replacement of a deteriorating culvert that carries Tuck Creek beneath the road. Local access will be maintained east and west of the construction zone, but all through-traffic will be detoured south to NE Novelty Hill Road.
A section of NE Woodinville Duvall Road, one of King County’s most heavily used east-west routes, will close for 30 days starting at 8 a.m. Monday, July 17. King County Road Services will remove a failing metal pipe culvert that carries Tuck Creek under the road near the intersection of NE 172nd Street. The old pipe is considered a fish passage barrier. The new culvert will be made of concrete and will be much wider to make it easier for fish to pass under the road.
Construction work requires road crews to dig a large pit across both lanes of NE Woodinville Duvall Road at NE 172nd Street. There is not enough room to keep one lane open or build a temporary bypass lane around the work zone.
Two-way local traffic will be able to go up to the closed-off construction area on each side, however no vehicles, bicycles or emergency response will be able to pass through the work zone because there will be a large open construction pit in the way. Drivers will follow an 11-mile-long signed detour south via NE Novelty Hill Road 24 hours a day.
This closure is essential to address the poor condition of the existing culvert, which, if left as is, could collapse and potentially wash out the entire road.
“We know closing one of one of our busiest roads for 30 days is a major inconvenience, but it is necessary to ensure the safety of the traveling public and avoid an even longer road closure in the future,” said County Road Engineer JoAnn Kosai-Eng. “The culvert that carries Tuck Creek under NE Woodinville Duvall Road has outlived its lifespan and is in danger of collapsing. If it does, not only will the culvert fail, but the roadway surrounding it could also collapse and have to be closed for up to one year.”
King County Road Services is working with the county’s Department of Natural Resources and Parks to replace culverts that were built under county-owned roads and trails but now block salmon from swimming upstream. This is part of the county’s fish passage restoration program.
Fish passage benefits
The existing round metal pipe culvert is considered a fish passage barrier for two main reasons:
- It is too small for the volume of water that passes through it. As a result, the water is pushed through extremely fast making it nearly impossible for fish to swim in it.
- At times, the water inside the existing culvert is too shallow and it is located too high above the stream bed for fish to jump into the culvert so they can continue to swim upstream.
Fish have a very difficult time swimming through extremely swift water, especially at the end of their spawning journey. They also have a lot of trouble jumping up and through a metal pipe with very little water in it.
Benefits of the concrete box culvert
A box culvert is flat and wide with streambed gravels placed in the bottom to simulate an actual stream allowing fish to move up and downstream easily. The new concrete box culvert will make it much easier for fish in Tuck Creek to pass under the roadway and continue their migration to Snoqualmie River:
- The box culvert can accommodate a much larger volume of water.
- It is designed to simulate a natural stream and allow consistent, gentle water flow under the road.
- NE Woodinville Duvall Road at NE 172nd Street Culvert Replacement Project website
- Fish Passage Restoration Program
- JoAnn Kosai-Eng, County Road Engineer, Road Services Division: “We know closing one of one of our busiest roads for 30 days is a major inconvenience, but it is necessary to ensure the safety of the traveling public and avoid an even longer road closure in the future. The culvert that carries Tuck Creek under NE Woodinville Duvall Road has outlived its lifespan and is in danger of collapsing. If it does, not only will the culvert fail, but the roadway surrounding it could also collapse and must be closed for up to one year.”